Light reflector



L. A. BEAN LIGHT REFLECTOR Feb. 18, 1930.

Filed Sepf. 11, 1928 gwuzntoq lav/.5 54-740 Patented Feb. 18, 1930UNITED STATES LOUIS A. BEAN, OF DENVER, COLOR-ADO LIGHT REFLECTORApplication filed September 11, 1828. Serial No. 305,218.

This invention relates to a reflecting surface more particularlyintended for flood lighting or spreading light rays over a relativelywide area. It will be found especially useful for photographic purposesfor illuminating interiors where natural light is not suflicient orexteriors at night. While the invention will be found particularlyuseful for photographic illumination it is not, of

course, limited to this use but can be employed for automobileheadlights and the like, where it is desired to spread the light over awide, horizontal, fan-shaped area.

The principal object of the invention is to provide a highly efficientreflector for the above uses.

Another object of the invention is to provide a photographic light whichcan be used with a series of light sources so that differing 2intensities and diflering degrees of concentration can be obtained.

Other objects and advantages reside in the detail construction of theinvention, which is designed for simplicity, economy, and efiiciency.These will become more apparent from the following description.

In the following detailed description of the invention reference is hadto the accompanying drawing which forms a part hereof. Like numeralsrefer to like parts in all views of the drawings and throughout thedescription.

In the drawing: a Fig. 1 is a front elevation of my improved reflectorwith the light sources outlined in broken line therein.

Fig. 2 is a vertical section through the reflector taken on the line 22,Fig. 1, illusrating one of the light sources in place.

Fig. 3 is a vertical section taken on the line 3 3, Fig. 2.

The outline of the open face of the reflector comprises two straightedges 10, joined at their extremities by semi-circular curved edges 11.Extending rearwardly from each straight edge 10 is a parabolical surface12.

These surfaces present a straight line when out by a plane parallel tothe open face of the reflector and substantially a parabola when out bya vertical plane at right angles to the face of the reflector. Thesurfaces 12 appreach the outline of an ellipsoid in front elevation.

Extending rearwardly from each of'the curved edges 11 is a concavesemi-ellipsoidal surface 13. The ellipsoidal surfaces 13 narrow as thecenter of the reflector is approached and join each other at the centralback of the reflector in a narrow curved band 20. The surfaces 13 jointhe parabolical surfaces 12 at tangent points therewith, the joiningline or line of tangency being a paraboliform curve, as illustrated inbroken line at 1 1. The change in the curve between the two surfaces 12and the two surfaces 13 is gradual throughout its entire extent.

The surfaces 18 approach the shape of the surface of an ellipsoid butare not necessarily confined to this exact form. They each comprise asurface curved at its outer edge in a semi-circle and extending back ona flattened curve to a curve which will be approximately tangent to orpart of the apex point of the parabaloid defined by the two surfaces 12.

I therefore, have an approximate ellipsoid cut through its two longersides by a pair of parallel, substantially parabolic surfaces. In thefinished reflector the line of tangency between the parabolical surfacesand the curved surfaces is so blended as to not be distinctly defined.'It is noticeable, however, by the contrasting reflections from thejoining surfaces. Any vertical plane parallel to the reflector openingwill cut. an outline from the reflecting surface similar to the out lineof the open face, such as illustrated in Fig. 3.

The reflector can be illuminated from a central light source 16, therebeing an opening 15 provided for the passage of the socket thereof, orit can be illuminated from two side lights 17 which may be supportedthrough side openings 18.

If desired all of the lights 16 and 17 may be employed to give a widespread evenly intensified beam. For a more localized concentration ofthe light for portraits and the like, the central light 16 only may beemployed.

The light sources should be connected with suitable control devices sothat they can be dimmed or brightened or operated independently to givethe desired localization or spread and intensity of illumination to thesubject.

lVith the central light source illuminated, the beams striking thereflector upon a vertical central line will be thrown straight forwardlyfrom the parabolical surfaces 12. The beams striking these surfaces ateach side of the center line will be deflected to an outward horizontalangle depending of course, upon their angle of incidence. The beamstraveling to the outer edges and striking the curved surfaces 13 will bespread outwardly at a greater angle than the beams from the surfaces 12,owing to the relatively flat ellipsoidal contour of the surface.

The vertical contour need not be an exact parabola but should approachthis shape. For instance, if made slightly deeper than a parabola itwill concentrate at a shorter dis tance and is useful for indoorphotography. If desired for illuminating exterior distant subjects thereflector should approximate a r parabola more closely to obtain thegreatest area of vertically parallel rays possible.

WVhile a specific form of the improvement has been described andillustrated herein, it is desired to be understood that the same may bevaried, within the scope of the appended claims, without departing fromthe spirit of the invention.

Having thus described the invention, what I claim and desire secured byLetters Patent is 1. A light reflector comprising two concave surfacesrounded at their outer edges and narrowed at their inner edges, said twosurfaces joiningeach other at said narrowed portions and two othersurfaces joined to said concave surfaces so as to fill in the narrowedportions thereof, said two other surfaces being curved in one plane onlythe line of joining forming a parabolic curve about the latter twosurfaces.

2. A light reflector comprising two c0ncave surfaces rounded at theirouter edges and narrowed at their inner edges, said two surfaces joiningeach other at said narrowed portions and two other surfaces joined tosaid concave surfaces so as to fill in the narrowed portions thereof,said two other surfaces being curved in one plane only in combinationwith a pair of light sources placed opposite said two first surfaces anda third light source placed opposite said narrowed portion.

In testimony whereof, I affix my signature LOUIS A. BEAN.

